CVE-2023-36832: Junos OS: MX Series: PFE crash upon receipt of specific packet destined to an AMS interface

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-14 · updated 2026-06-17
Weakness: CWE-755

Description

An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS on MX Series allows an unauthenticated network-based attacker to send specific packets to an Aggregated Multiservices (AMS) interface on the device, causing the packet forwarding engine (PFE) to crash, resulting in a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue is only triggered by packets destined to a local-interface via a service-interface (AMS). AMS is only supported on the MS-MPC, MS-MIC, and MX-SPC3 cards. This issue is not experienced on other types of interfaces or configurations. Additionally, transit traffic does not trigger this issue. This issue affects Juniper Networks Junos OS on MX Series: All versions prior to 19.1R3-S10; 19.2 versions prior to 19.2R3-S7; 19.3 versions prior to 19.3R3-S8; 19.4 versions prior to 19.4R3-S12; 20.2 versions prior to 20.2R3-S8; 20.4 versions prior to 20.4R3-S7; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S5; 21.3 versions prior to 21.3R3-S4; 21.4 versions prior to 21.4R3-S3; 22.1 versions prior to 22.1R3-S2; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R2-S1, 22.3R3; 22.4 versions prior to 22.4R1-S2, 22.4R2.

Affected products

Juniper Junos OS: before 19.1; 19.1, 19.1-r1, 19.1-r1-s1, 19.1-r1-s2, 19.1-r1-s3, 19.1-r1-s4 (+174) — fixed in 19.1

How to fix

Upgrade to a fixed version: Juniper Junos OS 19.1. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-36832 or the next vulnerability affects your stack